1. Field of the Invention
The present invention relates to a heat sink assembly, and particularly to a heat sink assembly having a fixing device for readily and firmly attaching a fan to a heat sink.
2. Related Art
Developments in today""s highly information-intensive society have led to remarkable improvements in performances of electronic devices. During operation of many contemporary electronic devices such as CPUs, large amounts of heat are produced. Such heat must be quickly removed from the electronic device, to prevent the system from becoming unstable or being damaged. Typically, a heat sink together with a fan is attached to an outer surface of the device to facilitate removal of heat therefrom.
Referring to FIG. 4, a conventional means for attaching a fan 300 to a heat sink 100 is by using screws 200. Each screw 200 engages with corresponding threads in fins 102 of the heat sink 100. Because modern CPUs generate large amounts of heat, contemporary heat sinks have fins with large depth-to-width ratios. The fins are relatively thin, which enables them to remove heat more efficiency. But an adverse result is that, during installation of the screws 200, there is increased risk of accidental damage to the fins in the vicinity of the threads. Furthermore, such fins are more pliable, and the screws 200 can loosen over time when the system is subjected to normal operating disturbances such as vibration. Moreover, chips may be torn off the threads of a heat sink while the screws 200 are installed. Such loose chips can migrate to other parts of the computer system during installation or use, where they may cause malfunction or damage.
Examples of convention heat sink assemblies are disclosed in Taiwan Patent Applications Nos. 84207163 and 86216714.
An improved means of securing a fan to a heat sink, which overcomes the above problems, is desired.
Accordingly, an object of the present invention is to provide a heat sink assembly having a fixing device which firmly and reliably attaches a fan to a heat sink.
Another object of the present invention is to provide a heat sink assembly which is readily assembled and disassembled.
To achieve the above-mentioned objects, a heat sink assembly of the present invention comprises a heat sink, a fan and a fixing device. The fan has a chassis, and a hollow cylinder extending upwardly therefrom. The heat sink has a base which defines a pair of grooves in a bottom surface, and a plurality of fins with a transverse slot defined through the fins. The fixing device comprises a body, and four resilient legs depending from corners of the body. A pair of lips depends from opposite edges of the body. A tab extends inwardly from a bottom edge of each lip, for engaging in the slot of the heat sink and thereby preventing the fixing device from moving laterally. A hook is formed at a distal end of each leg, for engaging in the grooves of the heat sink and thereby attaching the fan to the heat sink.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with the attached drawings, in which: